Sheet processing apparatus

ABSTRACT

A sheet processing apparatus includes a sheet tray, a processing unit configured to process one or more sheets that are placed on the sheet tray, a supporting member that is movable into and out of a conveying path of a sheet to be placed on the sheet tray, and a driving unit configured to move the supporting member into and out of the conveying path of the sheet. The supporting member includes a sheet support section that supports the sheet when the supporting member is moved into the conveying path.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2013-063259, filed Mar. 26, 2013, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a sheet processingapparatus and an image forming apparatus having the same.

BACKGROUND

A sheet processing apparatus is generally attached to an image formingapparatus and carries out a processing of a sheet conveyed from theimage forming apparatus. One type of the sheet processing apparatusperforms predetermined post-processing such as sorting and stapling ofone or more sheets. When a new sheet is conveyed from the image formingapparatus while the sheet processing apparatus is carrying out thepost-processing on the one or more sheets, the new sheet needs to be putaside until the post-processing is completed. The sheet processingapparatus employs a large mechanism for putting aside the new sheetuntil the post-processing on the one or more sheets is completed.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a sheet processing apparatus according to afirst embodiment.

FIG. 2 is a cross-sectional view of the sheet processing apparatusaccording to the first embodiment.

FIG. 3 is a perspective view of a processing tray of the sheetprocessing apparatus at a first position.

FIG. 4 is a perspective view of the processing tray at a secondposition.

FIG. 5 is a cross-sectional view of a paddle in the sheet processingapparatus.

FIG. 6 is a perspective view of the paddle shown in FIG. 5.

FIGS. 7-15 each are a cross-sectional view of the sheet processingapparatus carrying out a processing of sheets.

FIG. 16 is a perspective view of a processing tray of the sheetprocessing apparatus according to a second embodiment.

FIGS. 17A and 17B each are a perspective view of the processing trayaccording to a modified embodiment.

DETAILED DESCRIPTION

According to an embodiment, a sheet processing apparatus includes asheet tray, a processing unit configured to process one or more sheetsthat are placed on the sheet tray, a supporting member that is movableinto and out of a conveying path of a sheet to be placed on the sheettray, and a driving unit configured to move the supporting member intoand out of the conveying path of the sheet. The supporting memberincludes a sheet support section that supports the sheet when thesupporting member is moved into the conveying path.

Hereinafter, embodiments for carrying out the present exemplaryembodiments will be described with reference to the drawings.

First Embodiment

FIG. 1 is a block diagram of a sheet processing apparatus 200 accordingto a first embodiment. The sheet processor 200 includes a controller210, a sensor 230, and a driving unit 235. Each unit of the sheetprocessor 200 is mutually connected through a bus 300.

The controller 210 includes a processor 212 formed by a CentralProcessing Unit (CPU) or a Micro Processing Unit (MPU), a memory 214,and a storing device 220. The memory 214 is, for example, asemiconductor memory, and includes a Read Only Memory (ROM) 216 forstoring various control programs and a Random Access Memory (RAM) 218for providing a temporary working space to the processor 212. Thestoring device 220 is, for example, a hard disk drive and the othersemiconductor storing device such as a magnetic storing device, anoptical storing device, or a flash memory, or it may be a combinationthereof. The controller 210 communicates with a main controller 110 ofan image forming device 100. The controller 210 controls the sheetprocessor 200, based on the information received from the maincontroller 110 or various programs stored in the ROM 216 or the storingdevice 220.

The sensor 230 transmits inputs from respective sensors to thecontroller 210. The driving unit 235 controls respectively correspondingdriving mechanisms depending on an instruction from the controller 210.

FIG. 2 is a cross-sectional view of the sheet processing apparatus 200.The sheet processing apparatus 200 performs the post-processing such asstapling and sorting on a sheet. The sheet processing apparatus 200includes an inlet roller pair 240, a branching unit 242, a first sheetdischarge roller pair 244, and a fixed tray 248, each being positionedalong a sheet conveying direction. The sheet processing apparatus 200further includes an outlet roller pair 246, a processing tray 250, apaddle (revolving unit) 270, a stapler 280, and a sheet discharge tray290, each positioned downstream in the sheet conveying direction withrespect to the branching unit 242.

The inlet roller pair 240 receives a sheet on which an image is formedby an image forming unit of the image forming device 100, and conveysthe sheet to the branching unit 242. The branching unit 242 guides thesheet to the first sheet discharge roller pair 244 or the outlet rollerpair 246, according to an instruction of the controller 210 based on thetype of the processing on the input sheet. The first sheet dischargeroller pair 244 discharges a sheet to the fixed tray 248. The fixed tray248 stores a sheet on which an image is formed by, for example, a copyfunction of the image forming device 100. The outlet roller pair 246conveys a sheet towards the processing tray 250. The paddle 270 guides asheet buffered on a supporting member to the processing tray 250.

The processing tray 250 receives sheets conveyed from the outlet rollerpair 246. The sheets received by the processing tray 250 are, forexample, sorted and stapled. The stapling process is performed by astapler 280 provided upstream in the sheet conveying direction of theprocessing tray 250 (hereinafter, referred to as upstream), at apredetermined position of the sheets. The processed sheets aredischarged to the sheet discharge tray 290.

The sheet discharge tray 290 stores the sheets discharged from theprocessing tray 250. The sheet discharge tray 290 in this embodiment isa movable tray which moves vertically depending on a sheet dischargefrom the processing tray 250 or the loaded amount of sheets. The sheetdischarge tray 290 moves vertically when, for example, a sheet detectionsensor detects the upper surface of a sheet that is discharged in thesheet discharge tray 290.

Here, the fixed tray 248, the processing tray 250, and the sheetdischarge tray 290 are inclined in a way in which the downstream sidethereof in the sheet conveying direction (hereinafter, referred to asdownstream) is disposed higher.

FIG. 3 is a perspective view of the processing tray 250 in the sheetprocessing apparatus 200 shown in FIG. 2. The processing tray 250includes a pair of lateral alignment plates (lateral alignmentmechanism) 252, a pair of longitudinal alignment rollers 254, and a pairof rear end stoppers (not shown), in order to align the sheets conveyedfrom the outlet roller pair 246. The lateral alignment plates 252 arerespectively provided on a sheet supporting surface accepting the sheetsin the processing tray 250 at the both ends in a width directionorthogonal to the sheet conveying direction (hereinafter, referred tothe width direction). The lateral alignment plates 252 align the sheetsin the width direction (lateral alignment) by being moved back and forthin the width direction at the same distance by a driving mechanism. Thelongitudinal alignment rollers 254 are provided in the middle in thewidth direction and at the rear end portion in the sheet conveyingdirection (hereinafter, referred to as the rear end portion) in theprocessing tray 250, with a space therebetween. The rear end stoppersprotrudes from the rear end portion of the processing tray 250 in adirection upstream thereof. The longitudinal alignment rollers 254 alignthe sheets in a longitudinal direction by conveying the sheets on thesheet supporting surface of the processing tray 250 upstream incooperation with second sheet discharge rollers 258 to the point of therear end stoppers.

Further, the processing tray 250 includes a pair of second sheetdischarge rollers 258, ejectors 260, a belt 262, and a claw 264, inorder to discharge the sheets to the sheet discharge tray 290. Thesecond sheet discharge rollers 258 are provided in a front end portionin the sheet conveying direction on the sheet supporting surface(hereinafter, referred to as the front end portion). The second sheetdischarge roller 258 of the embodiment includes, for example, fourdriving rollers. The ejector 260 protrudes upstream in the sheetconveying direction from the middle portion in the rear end of theprocessing tray 250. In the embodiment, two ejectors 260 are providedbetween the longitudinal alignment rollers 254 and be driven back andforth in the sheet conveying direction by a driving mechanism. Theejectors 260 convey stapled sheets so as to be caught by the claw 264.The claw 264 is attached to the belt 262. The belt 262 is conveyedaround a driving roller and a driven roller (not illustrated) providedin the processing tray 250. The claw 264 moves along the sheet conveyingdirection, according to the movement of the belt 262 that is caused bythe rotation of the driving roller. The claw 264 conveys the sheetspassed from the ejectors 260 from the processing tray 250 to the sheetdischarge tray 290, in cooperation with the second sheet dischargerollers 258.

The processing tray 250 further includes a supporting member 266 formedin an L-shape in order to “buffer” (i.e., temporarily support) a sheet.The supporting members 266 are respectively provided on the both sidesin the width direction outside the movement range of the lateralalignment plates 252 on the processing tray 250. The supporting members266 are connected to the processing tray 250 and driven between a firstposition and a second position around a connection portion connected tothe processing tray 250 as a rotational axis. The driving mechanism is,for example, a motor or a solenoid. The above-described position of thesupporting members 266 is only one example. That is, the supportingmembers 266 may be arranged at any position as long as it does notinterrupt the moving of the lateral alignment plates 252 on theprocessing tray 250.

The first position of the supporting members 266 is in a state where thesupporting members 266 are open upwardly (refer to FIG. 3). Here, thesheets conveyed by the outlet roller pair 246 are conveyed onto theprocessing tray 250 without being interrupted by the supporting members266.

FIG. 4 is a perspective view of the supporting member 266 in the secondposition. The second position is in a state where the supporting members266 partially cover the top surface of the processing tray 250 on theinner sides of the lateral alignment plates 252 from the both sides.Here, a sheet conveyed by the outlet roller pair 246 falls down on thesupporting members 266 but is not on the processing tray 250. The sheetfalling down on the supporting members 266 slips to the upstream due tothe inclination of the processing tray 250 and the own weight of thesheet. The sheet is buffered in a state where the rear end stopped by apaddle 270 (refer to FIG. 10). In other words, the sheet is guided bythe supporting members 266 to the paddle 270. Therefore, the supportingmembers 266 are preferably arranged upstream of the processing tray 250.

Hereinafter, the operation of the supporting members 266 will bedescribed. When a sheet is conveyed to the processing tray 250, thecontroller 210 controls the supporting members 266 to be in the firstposition. In other words, when no processing is performed on a sheet onthe processing tray 250, the controller 210 controls the supportingmembers 266 to be at the first position. On the other hand, when someprocessing is performed on a sheet on the processing tray 250, thecontroller 210 controls the supporting members 266 to be at the secondposition. In other words, when a sheet is buffered, the supportingmembers 266 are at the second position. The processing in this casemeans, for example, longitudinal alignment, lateral alignment, stapling,or sheet discharge processing of the stapled sheets to the sheetdischarge tray 290. Further, by moving the supporting members 266 fromthe second position to the first position, the sheet placed on thesupporting members 266 falls down to the processing tray 250. Thesupporting members 266 maybe urged toward one of the first and secondpositions by an elastic mechanism such as a spring and rotated to theother position by a driving mechanism for driving in one direction.

FIG. 5 is a cross-sectional view of a paddle 270 in the sheet processingapparatus 200 shown in FIG. 2. The paddle 270 pushes a sheet buffered onthe supporting members 266 to the processing tray 250. The paddle 270rotates around a shaft. The paddle 270 includes a receiving portion 272,a tapping portion 274, and a forwarding portion 276. In this embodiment,a plurality of paddles 270 is provided in the width direction of theprocessing tray 250.

FIG. 6 is a perspective view of the paddles 270 shown in FIGS. 2 and 5.The paddles 270 further include a rear end chuck 278. The rear end chuck278 rotates coaxially with but independently from a receiving portion272, a tapping portion 274, and a forwarding portion 276. In theembodiment, the rear end chuck 278 is provided between the two paddles270 arranged in the middle in the width direction. The rear end chuck278 and the receiving portion 272 hold a sheet on the receiving portion272 by clamping the sheet therebetween. In short, a sheet is held by thetwo receiving portions 272 arranged in the middle in the width directionand the rear end chuck 278.

The respective members of the paddle 270 perform the followingoperations. The receiving portion 272 supports the rear end portion of asheet in a state where the sheet is placed on the supporting members 266(shown in FIG. 10). The tapping portion 274 pushes the sheet downwardwhen the sheet on the supporting members 266 falls down on theprocessing tray 250 (shown in FIG. 14). The forwarding portion 276 helpsthe sheet falling down on the processing tray 250 conveyed to the rearend stoppers by the longitudinal alignment rollers 254 (shown in FIG.15).

Hereinafter, referring to FIGS. 7 to 16, the processing of the sheetprocessing apparatus 200 and the operations of the processing tray 250and the paddles 270 according to the embodiment will be described withan example where two bundles of two stapled sheets are finished.

At first, a request to execute the post-processing such as stapling onsheets is input, for example, to the image forming device 100 connectedwith the sheet processor 200 and the request is transferred to thecontroller 210 of the sheet processor 200. Then, a sheet on which animage is formed is discharged from the image forming device 100 andreceived by the inlet roller pair 240 of the sheet processor 200 shownin FIG. 2. When there is no post-processing request, the branching unit242 discharges the sheet through the first sheet discharge roller pair244 to the fixed tray 248. On the other hand, when there is apost-processing request, for example, stapling request, the branchingunit 242 guides a first sheet P1 conveyed from the inlet roller pair 240to the outlet roller pair 246. The outlet roller pair 246 conveys thesheet P1 towards the processing tray 250. At this point, the supportingmembers 266 are moved by the driving mechanism to the first position asan initial position, and the sheet P1 falls down on the sheet supportingsurface of the processing tray (shown in FIG. 7). The controller 210performs processing for the lateral alignment and the longitudinalalignment on the sheet P1 placed on the processing tray 250, accordingto the lateral alignment plates 252, the longitudinal alignment rollers254, and the second sheet discharge rollers 258. A second sheet P2 isconveyed to the processing tray 250, according to the same operation asthe sheet P1 (shown in FIG. 8). When the longitudinal alignment and thelateral alignment on the sheet P2 are completed, the controller 210performs the stapling processing on a sheet bundle Pa of the sheet P1and the sheet P2.

During the stapling processing for the sheet bundle Pa, a third sheet P3is conveyed by the outlet roller pair 246 (shown in FIG. 9). Here, thesupporting members 266 are moved to the second position. As the sheetbundle Pa is being processed, the third sheet P3 is buffered on thesupporting members 266 that are moved to the second position. The sheetP3 is conveyed downstream while the front end portion of the sheet P3 issliding on the supporting members 266. When the rear end of the sheet P3is separated from the outlet roller pair 246, the sheet P3 slides in theupstream direction due to the inclination of the processing tray 250 andthe weight of the sheet itself. When the rear end of the sheet P3reaches the paddles 270, the sheet P3 is buffered in that position(refer to FIG. 10). When the sheet P3 is in a state of buffer, the rearend chuck 278 holds the sheet P3. For example, the rear end chuck 278holds the sheet when a detection sensor detects a sheet being on thesupporting members 266. Further, the controller 210 similarly causes afourth sheet P4 to be buffered on the supporting members 266 (refer toFIG. 11). The rear end chuck 278 is temporarily released when the sheetP4 reaches the paddle 270. When the sheet P4 is placed on the topsurface of the sheet P3, the rear end chuck 278 holds a sheet bundle Pbof the two (P3 and P4) (refer to FIG. 12).

When the stapling processing is performed on the first sheet bundle Pa,the sheet bundle Pa is discharged from the processing tray 250 to thesheet discharge tray 290, according to the operations of the ejector260, the claw 264 attached to the belt 262, the longitudinal alignmentrollers 254, and the second sheet discharge rollers 258 (refer to FIG.13). At this point, for example, even when the front end portions of thesheet P2 and the sheet P3 are in touch with each other, the sheet bundlePb held by the rear end chuck 278 will not follow the first sheet bundlePa. Next, after the discharge of the sheet bundle Pais completed, thecontroller 210 controls the driving unit 235 to drive the drivingmechanism, so as to move the supporting members 266 from the secondposition to the first position. In short, the supporting members 266perform the opening operation. When the supporting members 266 areopened, at the same time, the paddles 270 simultaneously rotate to dropthe sheet bundle Pb on the processing tray 250 (refer to FIG. 14).According to the operation of the supporting members 266 and the paddles270, the sheet bundle Pb on the supporting members 266 drops on theprocessing tray 250 (refer to FIG. 15). Since the sheet dischargeoperation of the sheet bundle Pb is the same as the operation of theabove-mentioned sheet bundle Pa, the description is omitted.

According to the first embodiment, by providing the supporting membersthat supports sheets above the processing tray, a mechanism forbuffering a sheet can be downsized. By buffering a sheet following asheet that is subject to a processing, more time can be secured for theprocessing. Further, as the sheet conveying time and the post-processingtime of a sheet are overlapped, the productivity of the sheet processingapparatus does not need to be compromised. Further, even when the frontend portions of the sheet bundle on the processing tray and the sheetbundle buffered on the supporting members are in touch with each other,the buffered sheet bundle is prevented from going out when the sheetbundle on the processing tray is discharged as the rear end chuck holdsthe buffered sheet bundle.

Second Embodiment

A sheet processor according to the second embodiment is different fromthe sheet processor 200 according to the first embodiment in thatsupporting members 266 a are provided on the upper portions of thelateral alignment plates 252.

FIG. 16 is a perspective view of the processing tray 250 according tothe second embodiment. The supporting members 266 a according to theembodiment are respectively provided on the upper portions of thelateral alignment plates 252. Specifically, in accordance with theoperation of the lateral alignment plates 252, the supporting members266 a are moved in the width direction. The supporting member 266 a isrotatable around a connection portion with the lateral alignment plate252 as a shaft. The supporting member 266 a is driven by a drivingmechanism such as a motor and a solenoid, similarly to the firstembodiment.

The lateral alignment plates 252 slide in the width direction during thesorting processing. When the supporting member 266 a is short in thewidth direction, a buffered sheet may drop down during the sliding ofthe plates 252. Therefore, it is preferable that the length in the widthdirection of the supporting member 266 a is formed longer at least thanthe sliding distance of the lateral alignment plate 252.

According to the second embodiment, the same effect as the firstembodiment can be achieved. Further, since the supporting members areintegrally formed with the lateral alignment plates, any sheet may bebuffered regardless of the size of a sheet.

According to at least one embodiment described above, as the supportingmembers that support a sheet are provided above the processing tray, itpossible to downsize a mechanism for buffering the sheet. By buffering asheet that follows a sheet to be processed, more time may be secured forthe processing. Further, as the sheet conveying time and the sheetpost-processing time are overlapped, the productivity of the sheetprocessor does not need to be compromised.

The disclosure is not restricted to the above embodiments, and variousmodifications are possible. FIGS. 17A and 17B are a modified example ofthe supporting member 266. The supporting member may be formed in ashape of extending in a downstream direction as illustrated in FIGS. 17Aand 17B. As the operation of the supporting member of this modifiedexample is the same as that of the second embodiment, the description isomitted.

Further, the number of the sheets to be buffered is not limited to twoas in the above embodiment. It may be properly changed depending on thesheet conveying speed and the processing time.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms. Furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein maybe made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A sheet processing apparatus comprising: a sheettray; a processing unit configured to process one or more sheets thatare placed on the sheet tray; a supporting member that is movable intoand out of a conveying path of a sheet to be placed on the sheet tray,the supporting member including a sheet support section that supportsthe sheet when the supporting member is moved into the conveying path;and a driving unit configured to move the supporting member into and outof the conveying path of the sheet.
 2. The sheet processing apparatusaccording to claim 1, further comprising: a holding unit configured tohold a rear end portion of the sheet placed on the sheet supportsection.
 3. The sheet processing apparatus according to claim 1, whereinthe driving unit moves the supporting member out of the conveying pathwhen the processing unit is not processing any sheets, and into theconveying path when the processing unit is processing sheets.
 4. Thesheet processing apparatus according to claim 1, wherein the processingunit includes a moving mechanism configured to move in a width directionorthogonal to a sheet conveying direction such that the sheets placed onthe sheet tray is moved in the width direction in accordance with themoving of the moving mechanism.
 5. The sheet processing apparatusaccording to claim 4, wherein the supporting member is disposed on themoving mechanism.
 6. The sheet processing apparatus according to claim4, wherein the supporting member is disposed at a position such that themoving mechanism does not interfere with the supporting member when themoving mechanism moves.
 7. The sheet processing apparatus according toclaim 1, wherein the supporting member is disposed at a positionupstream in a sheet conveying direction with respect to the sheet tray.8. A method for processing a sheet, comprising: conveying sheets througha sheet conveying path to a sheet tray as a supporting member having asheet support section is moved into and out of the sheet conveying path;and processing one or more of the sheets that are placed on the sheettray, wherein the sheet support section temporarily holds a conveyedsheet thereon when the processing of the one or more of the sheetsplaced on the sheet tray is being carried out.
 9. The method accordingto claim 8, wherein the conveyed sheet temporarily held by the sheetsupport section is released by the sheet support section when theprocessing of the one or more of the sheets placed on the sheet tray hascompleted.
 10. The method according to claim 9, further comprising:moving the supporting member into the sheet conveying path when theprocessing of the one or more of the sheets placed on the sheet tray isbeing carried out.
 11. The method according to claim 10, furthercomprising: moving the supporting member out of the sheet conveying pathwhen the processing of the one or more of the sheets placed on the sheettray has completed.
 12. The method according to claim 8, furthercomprising: holding a rear end portion of the sheet placed on the sheetsupport section.
 13. The method according to claim 8, furthercomprising: prior to said processing, moving the sheets placed on thesheet tray in a width direction orthogonal to a sheet conveyingdirection.
 14. An image forming apparatus comprising: an image formingunit configured to form an image on sheets; and a sheet processingapparatus that includes a sheet tray, a processing unit configured toprocess one or more sheets that are placed on the sheet tray, asupporting member that is movable into and out of a conveying path of asheet to be placed on the sheet tray, the supporting member including asheet support section that supports the sheet when the supporting memberis moved into the conveying path, and a driving unit configured to movethe supporting member into and out of the conveying path of the sheet.15. The image forming apparatus according to claim 14, wherein the sheetprocessing apparatus further includes: a holding unit configured to holda rear end portion of the sheet placed on the sheet support section. 16.The image forming apparatus according to claim 14, wherein the drivingunit moves the supporting member out of the conveying path when theprocessing unit is not processing any sheets, and into the conveyingpath when the processing unit is processing sheets.
 17. The imageforming apparatus according to claim 14, wherein the processing unitincludes a moving mechanism configured to move in a width directionorthogonal to a sheet conveying direction such that the sheets placed onthe sheet tray is moved in the width direction in accordance with themoving of the moving mechanism.
 18. The image forming apparatusaccording to claim 17, wherein the supporting member is disposed on themoving mechanism.
 19. The image forming apparatus according to claim 17,wherein the supporting member is disposed at a position such that themoving mechanism does not interfere with the supporting member when themoving mechanism moves.
 20. The image forming apparatus according toclaim 14, wherein the supporting member is disposed at a positionupstream in a sheet conveying direction with respect to the sheet tray.